1. Field of the Invention
The present invention relates to a seal assembly and method of sealing for use in high pressure application, for example, drilling and production applications. More particularly, the invention involves a seal assembly and method of sealing the junction between the male and female members or face seal members, wherein the seals are susceptible to explosive decompression effects.
2. Related Art
Ring seals are used in a variety of environments. Of particular interest are ring seals used in high-pressure environments. These include applications such as oil field drilling and production operations, hydraulic couplings, blowout preventer packings, etc.
Typical ring seals are often made from semi-permeable elastomeric materials. The sealing rings are intended to seal against a particular medium; if the pressure brought against the sealing rings by the medium becomes too great, the medium begins to penetrate the elastomeric material that constitutes the sealing rings. If a sudden pressure drop occurs in the surroundings of the sealing ring after such a penetration has occurred, the medium that has penetrated into the sealing rings abruptly expands. As a consequence of this expansion, the sealing rings are damaged or even destroyed. This kind of event is called an “explosive decompression.” This is a particular problem when the fluid is a gas at high temperature and pressure. In order to reduce the risk of an explosive decompression occurring, it is known to use seals, for example, o-rings, having a reduced cross-section and, as a result, a reduced exposed surface area. The likelihood of explosive decompression is also decreased by using seals made of materials having very low or very high permeability rates, such as costly and weaker silicone materials. Low permeability rates minimizes the incorporation of fluid in such materials, typically having a high durometer, thereby minimizing the effects of explosive decompression thereto. High permeability rates allows any fluid within such a material to be quickly released, thereby minimizes such effects thereto. Additionally, seal designers attempt to achieve a maximum volume fill of the seal gland partly to try to minimize such effects, but are constrained from doing so due to the thermal coefficient of expansion of the materials placed within the seal gland. Thus, a 100% volume fill cannot be accomplished. At best, about a 90% volume fill is attainable at room temperature.
There is a need to protect ring seals and provide a degree of resistance to explosive decompression regardless of the material that constitutes the ring seals.